Media magnate Rupert Murdoch's 21st Century Fox is abandoning its attempt to acquire U.S. media giant Time Warner.

The announcement Tuesday comes three weeks after Time Warner rebuffed 21st Century Fox's $80 billion offer to take over its movie studio, the popular movie channel HBO, Turner cable entertainment ventures and CNN, a worldwide news channel.

The merger would have combined two of the world's largest media companies.

Murdoch cited Time Warner's management and its board's refusal to come to the table to discuss a takeover as one reason for the stunning about face.

Murdoch's decision to walk away from his bid represents one of the biggest defeats in a decades-long career that began when he assumed control of his family's small newspaper company. The voracious deal maker has built one of the world's most powerful and influential media empires through his various takeover ventures.

Media watchdog groups concerned with the cultural impact of a merger of the two media conglomerates celebrated the withdrawal of Fox's bid. In a statement, Media Matters said "no one should hold that much influence."

Murdoch's reputation had been stained by the hacking scandal at his British newspapers, which led to the closure of his most profitable publication, The News of the World, and the arrest and conviction of senior staff.